Bacterial community dynamics during bioremediation of phenanthrene- and fluoranthene-amended soil

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants that enter the environment via incomplete combustion of fossil fuels and accidental leakage of petroleum products, and as components of products such as creosote. Bacterial community dynamics were examined in soils amended with two PAHs, phenanthrene or fluoranthene, and treated with fertiliser or aerated to stimulate the indigenous microbial population. Profiles of the bacterial communities present under a range of experimental conditions were generated using terminal restriction fragment length polymorphism (TRFLP) and the results were interpreted using sophisticated multivariate statistical analysis. Results indicated a distinct separation between community compositions based on time in phenanthrene-contaminated soil and a similar but less significant effect observed in fluoranthene-contaminated soil. High concentrations of fluoranthene had a positive effect on the abundance of some of the most dominant ribotypes. Aeration provided the most rapid treatment and resulted in almost complete removal of phenanthrene after 28 days.